Then she wondered if the horse like dogs and cats lie on their back sideways to catch their sleep.
I only know to answer that horse sleep standing up but behind the explaination, I do not know.
Its interesting, yeah horses do sleep standing up! And not be tired.
Imagine if God actually made us standing sleeping,…
Horses sleeping standing:-
The answer lies in a system of tendons and ligaments that work together with the knee cap. Animal experts call this the “stay apparatus.” It’s a pretty clever design, really. At any time, a horse needs only to relax the muscles on his front legs, and the stay apparatus will kick in. For the back legs, a horse must rotate its hips to activate the built-in locking mechanism.
Of course, the horse can sleep lying down if it so chooses, but God has designed this magnificent animal to get forty winks on four legs.